\section{Design}
An overview of the design of the desired product can be seen in \cref{fig:overview}. It is visible that the desired end-product consists of an eavesdropper and an emulator. In this section, more information will be given on these parts. 

\begin{figure}[ht!]
\centering
\includegraphics[]{Assets/Overview.png}
\caption{Overview of the design}
\label{fig:overview}
\end{figure}

\subsection{Eavesdropper}
It is possible to distinguish between two ways to steal data from a tag: skimming and eavesdropping. Skimming means that you use a reader to access information on the victim’s RFID tag directly without permission. Eavesdropping means that you listen in on the communication between an RFID tag and reader. The difference can be seen in \cref{fig:eavesvsskim}

\begin{figure}[ht!]
\centering
\includegraphics[]{Assets/EavesVsSkim.png}
\caption{The difference between eavesdropping and skimming \cite{hancke2011practical}}
\label{fig:eavesvsskim}
\end{figure}

Because a tag is passive, it is powered by the reader. This means that when the data is stolen with the use of skimming, the skimmer needs to power the tag. If the data is stolen with an eavesdropper, the reader will power the tag. As a result, eavesdropping is possible from a greater distance. Because of this, this project focusses on eavesdropping.

As explained in the introductory knowledge, a tag and reader together can be considered as a transformer and the tag communicates with the reader with the use of load modulation. An eavesdropper is a device with another inductor, which will be placed in the near field of the tag and the reader, so it will be able to receive the communication between the reader and the tag.

\begin{figure}
\centering
\includegraphics[width=\textwidth]{Assets/Block.pdf}
\caption{Blockdiagram of the eavesdropper}
\label{fig:blockdiagram}
\end{figure}

A block diagram of the eavesdropper can be found in \cref{fig:blockdiagram}. The first part of the eavesdropper is an antenna, which is needed to receive the signal.
Because the received signal will most likely be small with a lot of noise, the signal needs to be retrieved with a stage that filters and amplifies the signal. Before the signal can be used to find the UID, it needs to be demodulated. The output of the demodulation stage should be the information signal. This signal will then be processed: first it will be sampled and after that the signal can be decoded.

All these separate parts of the eavesdropper will be discussed in the following sections. The complete circuit design can be found in \cref{appendix:circuitdiagram}.

\input{Main/Design/Antenna.tex}
\input{Main/Design/AmplificationAndFiltering.tex}
\input{Main/Design/EnvelopeDetection.tex}
\input{Main/Design/Decoding.tex}

\input{Main/Design/Emulator.tex}
